Goiter

Goiter is a condition where your thyroid gland grows larger. Your entire thyroid can grow larger or it can develop one or more small lumps called thyroid nodules.

Your thyroid gland is a small, butterfly-shaped endocrine gland located in your neck, below your Adam’s apple. It produces the hormones thyroxine (also called T4) and triiodothyronine (also called T3). These hormones play a role in certain bodily functions, including:

• Metabolism.
• Body temperature.
• Mood and excitability.
• Pulse and heart rate.
• Digestion.

Goiter may be associated with an irregular amount of thyroid hormone in your body (hyperthyroidism or hypothyroidism) or with normal levels of thyroid hormone (euthyroid).

Goiter has several possible causes. Depending on the cause, it may or may not require treatment.

What are the types of goiter?

Goiter can be classified in a few different ways, including the way by which it grows and if your thyroid hormone levels are irregular or not.

Classifications for goiter based on how it enlarges include:

• Simple (diffuse) goiter: This type of goiter happens when your entire thyroid gland swells and feels smooth to the touch.
• Nodular goiter: This type of goiter happens when a solid or fluid-filled lump called a nodule develops within your thyroid and makes it feel lumpy.
• Multinodular goiter: This type of goiter happens when there are many lumps (nodules) within your thyroid. The nodules may be visible or only discovered through examination or scans.

Classifications of goiter based on thyroid hormone levels include:

• Toxic goiter: This goiter happens when your thyroid is enlarged and produces too much thyroid hormone.
• Nontoxic goiter: If you have an enlarged thyroid but normal thyroid levels (euthyroid), it’s a nontoxic goiter. In other words, you don’t have hyperthyroidism (overactive thyroid) or hypothyroidism (underactive thyroid).

Healthcare providers combine these descriptors to classify certain types of goiter when diagnosing them. For example, a toxic multinodular goiter happens when there’s more than one nodule on your thyroid — usually several — producing an extra amount of thyroid hormone.

Who does goiter affect?

Anyone can have a goiter, but it’s about four times more likely to develop in people assigned female at birth compared to people assigned male at birth. Your risk of developing goiter also increases as you age. They’re more common after age 40.

People who have any of the following conditions may also be more likely to develop goiter:

• Obesity.
• Insulin resistance.
• Metabolic syndrome.

You’re also at greater risk for developing goiter if your head and neck have been exposed to radiation for medical treatments and/or if you have a family history of thyroid disease.

How common is goiter?

Goiters are relatively common. They affect about 5% of people in the United States.

The most common cause of goiters worldwide is iodine deficiency, which affects an estimated 2.2 billion people.

The more severe the iodine deficiency, the more likely someone is to have goiter:

• With mild iodine deficiency, the incidence of goiter is 5% to 20%.
• With a moderate iodine deficiency, the prevalence increases to 20% to 30%.
• With severe iodine deficiency, the incidence increases to greater than 30%.